The subject of the present invention is a speed reducer of the type comprising at least one first reduction stage and one second reduction stage, in which the second stage has cylindrical gears with drive input and output shafts having parallel axes.
The term xe2x80x9creducerxe2x80x9d is used in this context in its most general meaning of a transmission member which can operate either to reduce or to gear up the relative speeds of a main drive input shaft and a main drive output shaft. A reducer including the characteristics listed above is known by the term xe2x80x9cCYCLO MODULAR SYSTEMxe2x80x9d and is produced by Sumitomo Cyclo Drive Europe Ltd.
This CYCLO transmission system is particularly useful when it is necessary to use a reducer with parallel or perpendicular axes having a high reduction ratio. It is very suitable for oscillating mounting. CYCLO reducers consist of a first cycloidal reduction stage combined with a second reduction stage with parallel axes, having a hollow drive output shaft. A main disadvantage of this transmission system is its axial bulkiness which, particularly for oscillating mounting, is unsuitable for certain applications in which axial compactness of the reducer is fundamental.
The main task of the present invention is to provide a speed reducer which is designed structurally and functionally to prevent the technical problems complained of with reference to the prior art mentioned.